Lathe



1. cmsum.

LATHE.

APPLICATION FILED JuLv 2a. 19w.

Patented Feb. 1, 1921.

3 SHEETS-SHEET I.

J. CARSON.

LATHE.

APPLlCATl(lN FILED JULY 23. 1918.

1,367,459. Patented Feb. 1, 1.921.

. a SHEETS-SHEET 2.

Wztwses J. CARSON.

LATHE.

APPLICATION FILED JULY 23 191-8.

Patented Feb. 1, 1921.

3 SHEETSSHEET 3.

WZZ/wsms. 2.. 1%. Wm 3 1 UNITED STATES PATENT OFFICE.

JAMES CARSON, OF 'I'O'ITENHAM HALE, ENGLAND, ASSIGNOR OF ONE-THIRD TO ARTHUR LYNAM CHURCHILL AND ONE-THIRD TO JOHN WILLIAM WRIGHT GABRIEL, BOTH OF LONDON, ENGLAND. I

LATHE.

Specification of Letters Patent.

Patented Feb. 1, 1921.

Application filed July 23, 1918. Serial No. 248.803.

subject of the King of Great Britain, residing at Fawley Road, Tottenham Hale, Mi ldlesex, England, have invented new and useful Improvements in Lathes, of which the following is a specification.

This invention relates to lathcs and other machine tools of the kind usually termed automatic, and the several operations of which are controlled by fluidpressure.

In machines of this class as heretofore used the traversing and feed movements of the tool supports have been directly effected by the fluid pressure, and have necessitated the special construction of the machine throughout.

The object of this invention is to apply to a lathe, drilling machine or like machine tool of ordinary construction, whether new or alread existing, and wherein the traverse of t e tool holders is effected by a screw or worm, a rack and pinion or other mechanical o erating device, means, controlled by flui pressure, for performing the operations usually effected by handand t ereby rendering such a machine practically automatic.

According to the said invention the spindles or other parts to be operated have combined with them means whereby rotary or longitudinal movement can be imparted to them, through the medium of pressure, preferably pneumatic, the application of which is controlled by cams orother devices actuated by the machine. For instance, in the case of a screw cutting lathe the invention will be applied for the purpose of moving back the tool from the work prior to the return movement of the saddle upon the bed, disen aging the nut from the leading screw to alow the return of the saddle, and a ain moving the tool to the requisite position for the next cut and reengaging the nut with the leading screw so that when a piece of work has been set in the lathe the latter may continue to run without attention until the desired operations are completed.

In order to stop the machine, when the tool carrying slide has reached a position corresponding to certain dimensions of the work, a valve can be provided for releasing the pressure from acylinder containing a piston which holds the belt striking mechan sm 1n the driving position against the action of a Weight or s ring.

To enable the invention to be fully understood 1t shall now be described by reference to the accom anying drawings, in which Figure 1 s ows an elevation of so much of a screw cutting lathe as is necessary to illustrate the application of my invention thereto, and which mechanism is indicated duigrammatically in the said figure, and F 1g. 2 IS an end view of parts shown in %igs. 3 to 14: are views drawn to varying scales to illustrate in detail various parts of the mechanism and which figures will be hereinafter described.

0; indicates the bed of the lathe, a the fixed headstock, a the sliding saddle, a the leading screw, a the change wheels through the medium of which the screw is driven from the lathe mandrel, a. the rack and a the pinion for moving the saddle longitudinally over the bed, all of which parts are of ordinary construction and require no description.

In describing the invention it is assumed that the work 15 "being rotated and that the' the order given.

1. To engage the lead screw nut with the lead screw, which latter receives its motion from the change wheel drive through the medium of a clutch b in a well known manner.

2. To give the requisite movement to the tool with relation to the slide rest for making the cut to the requisite depth.

3. To feed the rest carrying the tool up to the work.

4. To cause the lead screw to rotate throu h the operation of the clutch '6.

5. o 0 en the lead screw nut at the completion of the traversin movement.

6. To 0 erate the sli e rest to draw the tool out oi the work.

7. To move the saddle back to the position.

8. To open the clutch b to disengage the lead screw from the mandrel.

9. To engage the nut with the lead screw as described under 1, when the c cle of operations is repeated, and so on til the requisite number of cuts has been made.

10. To stop the lathe,

To enable the above movements to be effected pneumatic plstons and cylinders are 'represented in the accompanying drawings all of which are connected by means of suitable tubing with valve boxes connected with an air reservoir 0 common to them all, and in which air pressure is maintained by a suitable compressor.

The valves in the several valve boxes are controlled by a series of cams mounted on a common shaft d in a frame at, Fig. l, which shaft has intermittent rotary motion imparted to it by means of mechanism shown inost clearly in Figs. 3, 4, 5, 6 and 7, Fig. 3 being a sectional elevation of such shaft driving mechanism and Fig.4 a sectional plan; Fig. 5 an elevation of part of the mechanism (indicated in Fig. 3, in dotted lines), Fig. 6 a section onthe line 6-6, Fig. 5, and Fig. 7 a plan view of a detail. This mechanism comprises a worm wheel e mounted on the shaft d, and a worm c engaging therewith and fixed to a shaft 6 which is driven from a pulley e kept continually running by any suitable means. Between the pulley and the shaft e is a friction clutch f which is designed to be held in engagement with the pulley e by a spring 7.

The disengagement of the clutch 7 from the pulley e is effected through the medium of a bell-crank lever 7 Figs. 4 and 5, pivoted betweentwo lugs f", f (Fig. 3) on the frame (1 one arm f of which bell crank lever carries a fork f engaging in a groove in the clutch f while the other arm 7 is acted upon by a disk 7 carrying cam pieces f, f designed to bear in turn upon one end of a bar i sliding in a groove in the lever arm 7". The disk f is mounted u on the cam shaft d and rotates therewith. pon a rod g, Fig. 1, carried in suitable brackets upon the bed a are arranged stops 9 g which can'be adjusted according to the nature of the particular work being performed, and against which the saddle a is designed to impinge to move the said rod longitudinally. In connection with one end of this rod is a box it in which a cam bar 71. fixed to the rod 9 is free to slide. This cam bar has in it two sets of cam surfaces h it and h it, as will be understood by reference to Figs. 8 and 9, which are respectively an elevation of the said box'and a sectional plan of the bar h and parts cooperating therewith. These cam surfaces if, h and h h operate respectively upon a slide h and a lever h, the cam sur-' faces k [2. serving to lift the slide k and the cam surfaces h, k to operate the lever 72. The slide it carries a spring k which acts upon the end of a slide valve k of, say, ordinary D-type, which controls the admission of air from the reservoir 0 to a pneumatic cylinderz' upon the arm f of the bell crank lever 7", through pipes 71 i and the exhaust of such air from the said cylinder through retrace the said latter ipe The raising of the slide h serves, y bending the spring it to put a certain amount of pressure upon the valve it, so that when the latter is released, owing to the movement of the lever h under the action of the cam surfaces 72 n and the consequent disengagement of a lock h on the said lever from a notch in a slide it (two lugs upon which embrace the valve) the said spring will effect a quick movement of the said valve.

The return movement of the valve it is effected by a double inclined cam h on the cam bar k which cam h acts upon a roller on an extension of the slide k, the weight of the lever k causing the lock it to again engage with the said bar it.

The piston i of the cylinder 7? has its rod 2? in the form of a bar which has mounted upon it a pawl i which pawl is designed to cooperate with another pawl 2' on the bar f before referred to, in such a manner that when, on the admission of air into the cylinder 2' its rod 2' is pushed outward, the bar f will be moved a corresponding distance to withdraw it from contact with the campiece f or f of the disk 7" to force the clutch f into contact with the pulley 6 whereby rotary motion-will be transmitted to the cam shaft d.

In order to insure the accurate positioning of the shaft 03 and its cams with relation to the driving mechanism, there is arranged upon the frame d a sliding locking bar which is acted upon by a spring normally tending to push one end of the locking bar into one or two diametrically opposite notches f on the disk i in Fig. 3. This locking bar is has upon it a lug 70 with which a corresponding lug k on the bar f cooperates in such a manner that when the bar f is pushed backward by the movement of the piston rod 1', as above described, the locking bar is will also be moved leaving the disk i free to be rotated as before described, the rotation of the cam shaft (1 continuing until the opposite notch f comes into position for the engagement of the looking bar k with it. The release of the looking bar k from engagement with the bar f is effected during the rotation of the cam shaft by the action of a lever Z, Figs. 3, 4, 5 and 7. This lever Z is operated upon by a cam Z on the cam shaft d and serves, when in one position, to support the pawl 2' in the position shown in Fig. 5, in which the latter is in engagement with the pawl i When, however, at a certain point of the revolution of the cam P, the lever Z is allowed to drop, the-pawl'i also drops out of engagement with the pawl i whereupon a spring Z acting against one end of the bar f", pushes it into a position in which the other end again projects in front of the cam diskf, and this movement of the bar f also allows the en agement of the lockin bar In with one of t e notches f in the sai disk. At the same timethat the lockin bar 70 engages one of the notches f one 0 the cam-pieces f or f, by acting upon the projecting end of the bar 7, swings the bellcrank lever f and disengages the clutch i from the driving ulley e.

m, Fig. 1, is the pneumatic cylinder by means of which the lead screw nut is enga ed with the lead screw a, and m is the vafve for controlling the admission and exhaust of air into and from the said cylinder. 7

- The piston of this cylinder is shown as connected to a lever m on the spindle carrying the usual hand lever m for o erating the nut. The valve m is controlle by two cam-pieces m, m which are adjustable in a slot m in a drum m" mounted on the cam shaft d, a development of this drum being shown in Fig. 10 of the drawings.

Anyconvenient form of valve may be employed, and in Fig. 11, which is a section on the line 11-11, Fig. 1, a valve is shown which answers the purpose of the invention and which is of ordinary piston type operated by an oscillating lever m". This lever m is mounted on a shaft m" and has upon it two rubbing pieces m", m, with which the adjustable cam pieces m", m are desi ned to engage as the cam drum m is rotate the engagement of the cam piece m with the rubber m servin to oscillate the lever m and to put the va ve in one position and at the same time to bring the rubber m into such a position that as the rotation continues the cam-piece m will make contact with it to move the lever in the reverse direction. It will be understood that the relative positions of the cam-pieces m, m will determine the moment at which the air is to be admitted or exhausted through the pneumatic cylinder m to cause the engagement or disengagement of the nut as required.

n Fig. 1, is a pneumatic cylinder for imparting to the tool holder at maximum amount of feed movement with relation to the slide rest, and the admission of air into this cylinder is controlled by a valve a similar to the valve m and operated by cam pieces a, n arranged in the manner before described and properly adjusted in a slot a in the drum me". As shown in Figs. 12 and 13 of the drawings, which are views of this feed mechanism at right angles to one another the piston of the cylinder at is connected to an oscillating lever a carrying at one extremity a pawl en aging with a ratchet-wheel a" on the fee -screw of the slide rest.

As in executing any piece of work it ma be necessary to take a series of cuts consid erabl less than the maximum, there is provide in connection with the lever a a snail cam 0 having upon it a series'of steps which constitute stops for the corresponding step by step movement of the lever a as the cam is rotated. This snail cam 0 is mounted on the slide rest in a manner clearly shown in Figs. 12 and 13 so that it can be rotated through the medium of. a ratchet-wheel o and pawl 0 The pawl 0 is mounted on a slide 0 which is operated by the piston of a pneumatic cylinder 0, and the admission and exhaust of air into and from this cylinder is effected through a valve Fi 1, also similar to the valve m before diascri ed, and the operation of which is controlled by campiecesp, p adjustable in a slot 9 on the cam drum m".

The next operation to perform is to move the tool-carrying restup to the work, and this is effected by means of a pneumatic cylinder g, the piston rod of which is connected to a rack g engaging with a pinion g on the screw of the tool rest. The control of air for operating the piston at the required times is effected by the cam-pieces g, 91 adjustable in a slot 9' in the drum m and operating upon a valve g in the manner before indicated.

The tool being new in position to take a cut and the nut in engagement with the lead screw, the latter is cTutched to the changewheel drive by the clutch b, shown in sectional plan in Fig. 14 and this clutch is caused to make the necessary-engagement by means of a pneumatic cylinder 7', the admission of air to which is controlled through a valve 7' by means of cam-pieces r 9" in a slot 7* on the cam drum m". The lead screw a will now cause the traverse of the slide rest a along the bed until the said slide-rest strikes the stop 9 on the bar g, the efi'ect of which is to move the cam bar b from the position shown in Fig. 8 to cause the cam surfaces if, h to act upon the slide M and the locking lever it". As a result of this movement the valve it will be moved to admit air to the cylinder a and thereby enable the cam drum m to be connected to the pulley e by the friction clutch 7, whereby the said cam drum is caused to move until it is declutched by the operation of the campiece 8 on the slide f on the bell-crank lever f. his movement of the cam drum first causes the cam m to operate to disengage e the lead screw nut from the lead screw. T cam p then operates to allow the rotation of the snail cam 0 for determining the amount of tool feed. The cam 11 then operates to admit air to the cylinder at to move the feed lever a to the position indicated by the dotted lines in Fig. 12, the teeth of the pawl slipping over the teeth of the ratchet-wheel n so that on the next operation of the said lever a feed will take lace determined by the position of the snail cam o. g The cam 9 now operates its valve to admit air to the cylinder q, whereby the tool rest or clearance slide is drawn back to clear the tool to the starting position of-the thread being cut. When the saddle strikes the stop 9 the cam bar h will again be operated to cause a further rotation of the cam drum on). This causes the operation of the several valves m, p, n and g in the order stated for performing successively the following operations:

1. Closing the lead screw nut.

2. Moving the snail cam 0 to determine the amount of feed to be given to the tool.

3. Operating the lever 11 until it strikes the snail cam 0 to give the requisite feed; and

4:. Moving forward the tool rest or clearance slide.

At this point another cam-piece 8 in the slot s and not previously described, operates the valve s to allow the air from the cylinder 8 to be exhausted as the slide rest is traversed under the action of the lead screw.

Lastly, the cam-piece r operates the valve 0 to close the clutch Z), when the operations hereinbefore described are repeated.

It will be noticed that a spring g" is arranged at one end of the rod 9 to move the latter so as to bring the cams h", h and k k to a central position with relation to the slide h and lever h when the saddle a is moved out of contact with the collars 9 g 7 thereby causing the valve h to exhaust the air from the cylinder 71.

The movements hereinbefore described are repeated from time to time until the tool has been moved forward to the requisite depth of out, which is determined by the steps on the snail cam 0. At this point a pin 25 on the snail cam 0 comes into contact with the tail of a lever 25 connected with a two-way cock t which controls the supply of air to a pneumatic cylinder 25 in connection with the striking gear of the lathe, the rod 25 attached to the piston in the cylinder carrying the strap fork t. The air pressure is normally maintained in the cylinder i to hold the rod 6 against the pressure of a spring 5. The operation of the cock t by the lever t before referred to cuts off the supply of compressed air to the said cylinder and allows the airtherein to escape, with the result that the piston thereof is returned, under the action of the spring 23 to move the strap fork t to stop the lathe.

Although a pneumatic cylinder is shown and described for returning the saddle a spring, weight or rotary motor operating the pinion a can be employed.

It is to be understood that the above arrangement of pneumatic cylinders, valves, operating cams, etc., do-not in themselves form any part of the invention, but are simply given to illustrate how the various operations of a machine tool can be controlled mechanically at the required moments without the necessity for superintendonce.

It is also to be understood that instead of employing compressed air any other form of fluid pressure may be used.

Claims:

1. In a lathe, the combination with a bed, of a longitudinally movable reciprocating saddle, mechanical means for feeding the saddle along the bed in one direction and in the opposite direction by fluid pressure. a slide rest movable transversely of the saddle, means operated by fluid pressure for moving the slide rest toward and away from the work, a tool holder supported by the slide rest and capable of feeding movement toward the work, means operated by fluid pressure for so feeding the tool holder successively increasing amounts during successive reciprocations of the saddle, and means operated by fluid pressure for effecting the movements of the said parts in their proper order orsequence for turning or cutting a screw thread.

2. In a lathe, a slide rest, a tool holder supported by the slide rest, a feed screw for the tool holder, a ratchet wheel fixed to said screw, a lever carrying a pawl which cooperates with the ratchet wheel for turn ing the feed screw in one direction, mecha nism for automatically operating said lever,

' and means engaging said lever for limiting movement of the same, said last named means in operation permitting successively increased movement of said lever.

3. The combination with a lathe having a reciprocating saddle and a rotating mandrel, of a driving member rotating one member of a clutch, a driven member cooperating with another member of the clutch for receiving movement from the driving member, means actuated by said saddle for controlling engagement of the clutch members to permit the driving member to impart movement to the driven member, a lead screw'for moving the saddle in one direction, a lead screw nut cooperating with the lead screw, gearing including a clutch for driving the lead screw from said mandrel, fluid operated means controlling the last named clutch, and means actuated by said driven member for controlling the fluid operated means.

4. A combination as defined in claim 3, having fluid operated means for actuating the feed screw nut, and means actuated by the driven member for controlling the fluid operated means.

5. The combination with a lathe having a reciprocating saddle and a feed screw cooperating with a feed screw nut, of a cylinder, a piston mounted in the cylinder and having a rod, means connecting the rod with the feed screw nut, a source of pressure fluid, a valve controlling the admission and exhaust of pressure fluid from the cylinder, and automatically operating means for actuating said valve.

6. The combination with a lathe having a reciprocating saddle, of a driving member and a driven member, a clutch for coupling said members, means controlled by said saddle for causing the clutch to couple said members, a feed screw for the saddle, a feed screw nut cooperating with the screw, fluid pressure operated means for disengaging the not from the screw and means controlled by the driven member for actuating the fluid pressure means.

7. The combination with a lathe having a reciprocating saddle, of a driving member and a driven member, a clutch for coupling said members, means controlled by said saddle for causing the clutch to couple said n'iembers, fluid pressure operated means for moving the saddle in one direction, and means for actuating the fluid pressure operatcd means.

H. The combination with a lathe having a reciprocating saddle, of a driving member and a driven member, a clutch for coupling said members, means controlled by said saddle for causing the clutch to couple said member, a slide rest movable transversely of the saddle, a feed screw for the slide rest, fluid pressure operated means for actuating said feed screw, and means controlled by the driven member for actuating the fluid pressure operated means.

9. The combination with a lathe having a reciprocating saddle, of a driving member and a driven member, a clutch for coupling said members, means controlled by said saddle for causing the clutch to couple said members, a slide rest supported by the saddle, a tool holder movably mounted on the slide rest, a feed screw for the tool holder, fluid pressure operated means for actuating the feed screw, and means controlled by said driven member for actuating said fluid pressure means.

10. A combination as defined by claim. 9, in which the fluid pressure operated means includes mechanism for moving the feed screw successively increasing amounts during successive movements of the saddle.

11. A combination as defined by claim 9, in which the fluid pressure operated means supports a movable lug, a lever actuated by said lug, a valve controlled by said lever, and means controlled by the valve-for stopping the lathe.

JAMES CARSON. 

